Don't need screenshots
I'm assuming TP bonus earring also, because of course.
Code
Rudra (w/Aeneas @ 1000TP)
.8 * 8.8925 = 7.114
MStab (w/Vajra @ 1000TP)
.6 * 4.5225 * 1.3 = 3.52755
At 1000TP, Rudra with Aeneas is much stronger than MStab with Vajra, disregarding attack bonus.
Even under situations where Aeneas' TP bonus goes to waste AND you use SAWS, it'll still win.
Code
Rudra (w/ Aeneas @ 3000TP and SA)
.8 * 13 = 10.4
MStab (w/ Vajra @ 3000TP and SA)
.6 * 8.5 * 1.3 * 1.3 = 8.619
(I'm just using 1.3 for SA bonus even though it's not 100% accurate to simplify things, and it shows that giving this flawed bonus to MStab/Vajra will still show it as being behind)
It's not the Vajra is a weak dagger. It's that Rudra is monstrous in comparison.
Code
Rudra (w/ Vajra @ 3000TP and SA)
.8 * 13 * 1.3 = 13.52
For Vajra/Mstab to win, two things must happen: most/all of your WSs have to be paired up with SA/TA and it needs to be part of an effective skillchain. Higher TP will close the gap, but never eliminates it. Whatever benefit the attack bonus can offer will just be there for extra leverage. On the other hand, Aeneas's DMG is a good amount higher.
On the other-other hand, there is the issue with the effective +10% attack swing with Vajra's AM3. If it could push more 4-hit rounds to 3-hit rounds, or 3-hit rounds to 2-hit rounds, that could go some way towards evening things out again. There's also the minor bonus of more multi-hits going off during WSs. There's also the situation where gaining TP more quickly would make a huge difference. Once the math gets that complicated, I really lose interest in trying to figure it out.
Long story short, Vajra has its niche use in specific situations, and I didn't add anything to the conversation because people already knew that.